Herein, one-pot conversion of cellulose to platform chemicals, formic and levulinic acids was demonstrated. The catalyst selected was an affordable, acidic ion-exchange resin, Amberlyst 70, whereas the cellulose used was sulfite cellulose delivered by a Swedish pulp mill. Furthermore, in an attempt to better understand the complex hydrolysis network of the polysaccharide, kinetic experiments were carried out to pinpoint the optimal reaction conditions with an initial substrate concentration of 0.7-6.0 wt% and a temperature range of 180-200°C. Higher temperatures could not be used due to the limitations in the thermal stability of the catalyst. Overall, maximum theoretical yields of 59 and 68 mol% were obtained for formic and levulinic acid, respectively. The parameters allowing for the best performance were reaction temperature of 180°C and initial cellulose concentration of 0.7 wt%. After studying the behavior of the system, a simplified reaction network in line with a mechanistic approach was developed and found to follow first order reaction kinetics. A satisfactory fit of the model to the experimental data was achieved (97.8 % degree of explanation). The catalyst chosen exhibited good mechanical strength under the experimental conditions and thus, a route providing green platform chemicals from soft wood pulp from coniferous trees (mixture of Scots Pine and Norway Spruce) was demonstrated.
Kinetics of homogeneously catalyzed hydroformylation of 1-butene was studied in a pressurized semibatch autoclave reactor. Kinetics was determined for a reaction mixture, which consisted of 1-butene, carbon monoxide, hydrogen, a rhodium-based catalyst, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate as a solvent. The following reaction parameters were investigated: temperature (70-100 °C), total pressure (1-3 MPa), catalyst concentration (100-200 ppm), catalyst (Rh)-to-ligand ratio, and the initial ratio of the synthesis gas (hydrogen and carbon dioxide) components. The solubility of 1-butene, carbon monoxide, and hydrogen in the solvent was determined by precise pressure and weight measurements and modeled mathematically. The main reaction products were pentanal (P) and 2-methylbutanal (MB), while trace amounts of cis-2-and trans-2-butene were detected as reaction intermediates. The ratio of the main products (P and MB) was practically independent of temperature, but the ligand-to-Rh ratio affected considerably the product distribution: an increasing ratio preferred the formation of pentanal (P). Increasing total pressure diminished the yield of pentanal (P). On the basis of the experimentally recorded kinetic data, a stoichiometric scheme was constructed and simplified. The kinetic data were combined with solubility models, and the parameters of an empirical power-law rate model were determined by nonlinear regression analysis. The kinetic parameters were well identified and physically reasonable being in accordance with qualitative observations.
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